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Date:   Fri, 13 May 2022 09:54:44 +0200
From:   Oscar Salvador <osalvador@suse.de>
To:     Rei Yamamoto <yamamoto.rei@jp.fujitsu.com>
Cc:     akpm@linux-foundation.org, mgorman@techsingularity.net,
        vvghjk1234@gmail.com, aquini@redhat.com, ddutile@redhat.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm, compaction: fast_find_migrateblock() should return
 pfn in the target zone
Message-ID: <Yn4OxDIsl3OfB+6W@localhost.localdomain>
References: <20220511044300.4069-1-yamamoto.rei@jp.fujitsu.com>
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On Wed, May 11, 2022 at 01:43:00PM +0900, Rei Yamamoto wrote:
> Prevent returning a pfn outside the target zone in case that not
> aligned with pageblock boundary.
> Otherwise isolate_migratepages_block() would handle pages not in
> the target zone.
> 
> Signed-off-by: Rei Yamamoto <yamamoto.rei@jp.fujitsu.com>

Reviewed-by: Oscar Salvador <osalvador@suse.de>

> ---
>  mm/compaction.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index fe915db6149b..de42b8e48758 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -1858,6 +1858,8 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
>  
>  				update_fast_start_pfn(cc, free_pfn);
>  				pfn = pageblock_start_pfn(free_pfn);
> +				if (pfn < cc->zone->zone_start_pfn)
> +					pfn = cc->zone->zone_start_pfn;
>  				cc->fast_search_fail = 0;
>  				found_block = true;
>  				set_pageblock_skip(freepage);
> -- 
> 2.27.0
> 
> 

-- 
Oscar Salvador
SUSE Labs